EP2195325B1

EP2195325B1 - Activated silane

Info

Publication number: EP2195325B1
Application number: EP08802794A
Authority: EP
Inventors: Hagen HÜNIG
Original assignee: Saint Gobain Isover SA France
Current assignee: Saint Gobain Isover SA France
Priority date: 2007-10-04
Filing date: 2008-10-06
Publication date: 2011-08-10
Anticipated expiration: 2028-10-06
Also published as: WO2009043599A1; ATE519768T1; EP2195325A1; DE102007047373A1

Abstract

The present invention relates to an activated silane, to a method for producing the latter, to use of the activated silane as a component of a binder for mineral wool, and to a mineral wool product, wherein the activated silane is obtainable, e.g., by reacting a silane with a ketone which forms an acetal or semiacetal with a C1 to C12 alkyl or cycloalkyl alcohol or which forms a geminal diol with water, or with an open-chain or cyclic acetal or semiacetal or geminal diol of a ketone, wherein the acetal, semiacetal or geminal diol corresponds to the following formula (I).

Description

The present invention relates to a process for preparing an activated silane according to claim 1.
In the manufacture of bound mineral wool products from a molten glass or mineral material, it has for a long time been accepted practice to apply, following fiberization of the molten material, a binder on the basis of phenol-formaldehyde resin onto the fibers while still hot. This is preferably done inside the chute following fiberization, for example in accordance with the blast drawing method according to DE 35 09 426 A1 .
Here a phenol-formaldehyde resin, being the best-known binder in the prior art, is preferably sprayed on the fibers in the form of an aqueous solution or dispersion, with the phenol-formaldehyde resin then beginning to polymerize on the fiber surface owing to the still relatively high temperatures of the fibers and interconnecting the individual fibers by the polymerization process, in particular at crossing points of fibers, because the fibers overlying each other on a crossing point are embedded there, more or less, by solidified droplets of resin, whereby the mobility of the individual fibers among each other is initially impeded and later on prevented substantially entirely during curing by means of hot gases, for example in a tunnel oven.
Such a binder is described, e.g., in US 3,231,349 . For reasons of environmental protection and for reasons of workplace safety, attempts are in the meantime increasingly being undertaken to replace the classical phenolic resin binders, because of their formaldehyde content and their formaldehyde emission, with alternative, formaldehyde-free binders.
Further, EP 0297602 A2 relates to a sizing agent for the treatment of glass fibers which are incorporated in thermoplastic materials for reinforcement as well as a process for manufacturing a sizing agent. The sizing comprises a reactive silane in the form of a Schiffs base.
Thus, e.g., DE 10 2005 056 791 A1 for the present application describes a curable, formaldehyde-free, aqueous binder composition for glass and mineral wool fibers on the basis of polymer polyacids, an amine, and an activated silane.
As for an activated silane, it is disclosed in DE 10 2005 056 791 A1 in the framework of a binder composition including further components, that:

it is obtainable by reacting a silane, selected from the group comprising: mono-, di-, and trialkoxysilanes including a C₁ to C₈ alkoxy group, wherein the alkoxysilane carries at least one C₂ to C₁₀ aminoalkyl group or a C₂ to C₁₀ N-aminoalkyl group; 3(2-aminoethylamino)propyl-trimethoxysilane; (MeO)₃-Si-(CH₂)₃-NH-(CH₂)₃-Si-(OMe)₃; 3-aminopropylsilanetriol; aminosilane with ethoxylated nonyl-phenolate; phenyl-CH₂-NH-(CH₂)₃-NH-(CH₂)₃-Si-(OMe)₃*HCl; as well as mixtures thereof;

Starting out from this prior art, it accordingly was an object of the present invention to furnish further additives for binder compositions, in particular formaldehyde-free ones for mineral fibers, having after curing properties comparable with those of a phenol-formaldehyde binder without, however, having the emission problems of the latter, in particular in the manufacture of mineral wool products.
This object is achieved throug a method for producing an activated silane, characterized by reacting a silane, selected from the group comprising: mono-, di-, and trialkoxysilanes including a C₁ to C₈ alkoxy group, wherein the alkoxysilane carries at least one C₂ to C₁₀ aminoalkyl group or a C₂ to C₁₀ N-aminoalkyl group; 3(2-aminoethylamino)propyl-trimethoxysilane; (MeO)₃-Si-(CH₂)₃-NH-(CH₂)₃-Si-(OMe)₃; 3-aminopropylsilanetriol; aminosilane with ethoxylated nonyl-phenolate; phenyl-CH₂-NH-(CH₂)₃-NH-(CH₂)₃-Si-(OMe)₃*HCl; as well as mixtures thereof
with
a ketone according to Formula (1) including at least one carbonyl group which forms an acetal or semiacetal with a C₁ to C₁₂ alkyl or cycloalkyl alcohol, or which forms a geminal diol with water; or
with
an open-chain or cyclic acetal or semiacetal or geminal diol of a ketone according to Formula (1):
wherein R1 and R2, being identical or different, are independently selected from the group comprising: H; C₁ to C₉ alkyl; C₂ to C₉ alkenyl including 1 - 4 double bonds, C₁ to C₉ hydroxyalkyl; aryl including 5 or 6 C atoms in the cycle or heteroaryl including 1 - 4 hetero atoms and 4 - 8 C atoms in the cycle, cycloalkyl including 5 - 10 C atoms, heterocycloalkyl including 1 - 4 hetero atoms and 4 - 8 C atoms in the cycle, carbonyl, carboxyl, C₁ to C₉ n-alkylcarbonyl having a position of the carbonyl function of 1 - 9, C₁ to C₉ alkoxycarbonyl, wherein the alkyl residue in particular is methyl, ethyl, propyl, or butyl;
and wherein the acetal, semiacetal or geminal diol corresponds to the following general Formula (2):
wherein R3 and R4, being identical or different, independently is C₁ to C₁₂ alkyl or C₁ to C₁₂ cycloalkyl or H, and R1 and R2 have the same meaning as in Formula (1)
or
wherein R3 is an n-alkyl residue including 2 - 5 C atoms, and R1 and R2 have the same meaning as in Formula (1) or R1 and R2 is equal to H and R3 is equal to 2-oxypropyl,
or
the silane is reacted with mixtures of the named acetals and geminal diols.
In terms of process technology, the object is achieved through the characterizing features of claim 1.
The activated silane prepared according to the present invention is, for example, suited as a component of a binder composition for mineral fibers according to DE 10 2005 056 791 A1 , containing:

➢ an aqueous dispersion of at least one polymer polycarboxylic acid;
➢ at least one amino compound of the general Formula (1)
wherein R1, R2 and R3, independently of each other, are equal to or different from H, and R1 corresponds to the general Formula (2):
with a value for n of 2 - 10 and R2 and R3, independently of each other, being equal to or different from H or corresponding to the general Formula (3):
➢ wherein m may assume a value of 1 - 50, and the molecular mass of the amino compound does not exceed about 20,000 g/mol;

A preferred silane for producing the activatable silane according to the method of the present invention is 3-aminopropyltriethoxysilane. It is commercially available at low cost.
As carbonyl compounds for the manufacture of the activated silane, dihydroxyacetone or acetylacetone are preferably employed due to their easy availability, however the activated silane may also be produced with an enolizable ketone including at least one carbonyl group, or a ketone including at least one OH group, wherein the ketone contains 3 to 12 C atoms, or an alkyl-, aryl- or heteroaryl-substituted aldyehde, wherein acetalizitation in this case brings about an improved stability against oxygen.
The activated silane prepared according to the method of the invention is thus on the one hand suited as an additive for formaldehyde-free binders, but on the other hand also as an additive for conventional phenol-formaldehyde resin binders. For one thing, with the additive of the invention it is possible to manufacture absolutely formaldehyde-free mineral wool products, and on the other hand the binders and thus, of course, also the mineral wool products are water-resistant following curing.
For the manufacture of formaldehyde-free bound mineral wool with the binder component of the invention, the binder is applied onto the fibers while they are still hot following fiberization of a molten mineral material, and the mineral wool product with the applied binder is subjected to a curing process. Here the binder is applied on the fibers in particular by spraying the fibers attenuated from the molten mineral material inside the chute.
A bound mineral wool product thus manufactured satisfies any mechanical and chemical demands just like a mineral wool product bound by using classical phenol-formaldehyde resin.
Without being bound thereto, the activation of the silane with the acetal compounds appears to possibly unfold in accordance with the following reaction scheme, demonstrated on the ketal of acetylacetone:
As a result of the activation of the silane - in the above reaction scheme by way of the example of the γ-aminopropylsilanetriol having resulted from hydrolysis of 3-aminopropyltriethoxysilane - by reaction with the shown, exemplary acetals, there is formed on the activated molecule a "resin side" which is formed by the N part, in addition to a glass side formed by the Si part.
In the prior art, the amino group of the silane was reacted with formaldehyde into a Schiff's base which in turn reacted with the phenol-formaldehyde resin.
Thus a formaldehyde content of the binder as required in the prior art is not necessary any more because the activated silane carries an N-containing molecule portion which is capable of coupling to the binder resin - e.g., to the reaction product of the polyacrylate with the amine compound, particularly alkanolamine, but also to the ring of activated aromatic systems by performing a C- alkylation - which is thus bound via the silane linker to the glass surface of the hot fiber. These hydrolytic linkings take place rapidly on the fiber while it is still hot.
Further advantages and features of the present invention will become evident from the description of practical examples as well as from the drawings, wherein:

Fig. 1:: is a schematic view of silane coupled to a glass fiber via the Si portion of an activated silane; and
Fig. 2:: is a schematic view of a resin bound to a glass surface on a fiber via an activated silane.

The overall context by the example of the above mentioned binder composition with activated silane as a component in connection with the manufacture of mineral or glass fibers is once again visualized in Fig. 1 and Fig. 2.
Here the represented molecular arrangement should merely be understood in a schematic manner. Crosslinking reactions may, of course, for example still purposely take place inside the resin with crosslinking agents and with the alkanolamine, exemplarily polyacrylate. As a matter of fact it is also possible for unintended secondary reactions to occur, as is true with any polymerization. The contents of Figs. 1 and 2 may therefore merely be considered to be a model concept which is, however, helpful for an understanding of the invention.

Practical examples

The resins equipped with activated silane were tested in the laboratory and on the finished product in accordance with various testing methods. The results were compared with those of binder systems on the basis of the same base resins with silane in the absence of activation. Initially, the representation of the corresponding acetals from the corresponding alcohol and the respective carbonyl compound shall be described.

General operating prescription: 0.1 mole each of the corresponding carbonyl compound is boiled with 250 ml of the respective alcohol and 0.1 g of toluenesulfonic acid at the water separator until water does not pass over any more. Methylenechloride serves as an entraining agent. After completed reaction, entraining agent and excess alcohol are removed under vaccum. The residue is received with methylenechloride and shaken out with little-saturated sodium carbonate solution so as to remove the toluenesulfonic acid. The solution thus washed is dried with sodium sulphate. Then the solvent is removed, and the residue is dried. Purity of the product may simply be examined by IR spectroscopy as completeness of the reaction is identifiable by the absence of the respective carbonyl band at ~1700 cm^-1.

Table 1 Representation of the acetals

Carbonyl compound	Acetal	Mass 0.1 mole batch in g	Alcohol	Yield g / %
β-Resorcylaldehyde	1	13.8	Methanol	8.47 / 46
Thiophene-2-carbaldehyde	2	11.2	Methanol	8.54 / 54
Acetylacetone	3	10.0	Ethanol	22.1 / 89

The respective acetals were used with two different binders for activation of the silane.
Binder 1: What was used was a non-neutralized phenolic resin having a solids content of 46%, wherein the residual content of free formaldehyde was trapped by an activated aromatic substance. The aim was a binder having a solids content of 40%. Composition without acetal: 100 g of resin, 1.1 g of resorcinol, 0.5 g of 3-aminopropyltriethoxysilane, 17.8 g of water
Binder 1 without activation of the silane at the sime time served as Reference 1. Binder 2: What was used was a polyacrylic acid having a solids content of 50%, which was neutralized to a pH of 7.0 with ethanolamine. The aim was a binder having a solids content of 40%.
Composition without acetal: 100 g of resin, 0.5 g of 3-aminopropyltriethoxysilane, 83.1 g of water
Binder 2 without activation of the silane at the sime time served as Reference 2.
Activation of the silane generally took place in the following manner. The silane was charged in the respective dilution water and adjusted to a pH of 6.0 with the aid of hydroxyethanoic acid. Then the respective quantity of the acetal was added, and stirring was performed until an intense yellow coloration was observed. The solution of the silane was added to the respective binder batch. Table 2 Used amounts of the respective activator

Binder Acetal Mass in mg Variant

1 1 383 1.1

1 2 233 1.2

1 3 516 1.3

2 1 424 2.1

2 2 364 2.2

2 3 572 2.3

Determination of glass - resin adhesion

General operating method:
Circular glass pieces having a diameter of 7 cm, or a surface area of 38.5 cm², respectively, were used. The surface area was determined by counting with the aid of a grid template. The values were rounded.
On a circular piece of fire-polished glass having a composition in accordance with EP 1 522 532 A1 , 5 drops of a 20% binder solution are distributed homogeneously. The film is initially dried at 50°C in order to avoid inhomogeneities, and subsequently cured during 2 h at 150°C. The coated pieces are stored in water during 24 h at 70°C. Then the surface area proportion of the stripped resin is determined. A binder with a technically meaningful use should still adhere by at least 75% of the surface area to the glass after the test. The results are summarized in Table 3. Table 3: Proportion of stripped resin following storage at 70°C in water for 24 hours (indications rounded to integers)

Binder variant Area absolute in cm² Percentage

1.0 Reference 36 > 95

1.1 2 5

1.2 3 7

1.3 3 9

2.0 Reference 37 > 95

2.1 12 30

2.2 17 45

2.3 3 8
The results in Table 3 furnish positive evidence that an activation of the silane is necessary for a sufficient glass/resin adhesion, and that the imine should have a functionality that is well suited to the resin. This explains the comparatively poorer results in the case of activation of the polyacrylic acid with aromatic systems (2.1; 2.2).

With the respective binder variants, sample insulating materials having a nominal loss on ignition of 3.7% and a target bulk density of 50 kg/m³ at a thickness of 50 mm were prepared. The sample insulating materials were cut to sample pieces of 200x200 mm and subjected to the Nord test (7d, 70°C and 95% relative atmospheric humidity). The criterion used as a measure for the usefulness of the binder system was the thickness change after Nord test. In comparison, a board of this bulk density, following the complete removal of the binder by annealing, had a thickness of about 170 mm. In Table 4 the results of this testing method are shown.

Table 4 Thickness of sample insulating materials of one bulk density before and after Nord test (average values, rounded)

Binder variant	Thickness in mm before Nord test	Thickness in mm after Nord test
1.0 Reference	60	90
1.1	55	60
1.2	60	70
1.3	50	60
2.0 Reference	65	130
2.1	60	100
2.2	50	90
2.3	50	65

The results in Table 4 also furnish evidence for the positive effect of activation of the silane in contrast with the reference values. Likewise, the comparatively poorer efficiency of the activation with aromatic systems in the case of polyacrylic acid is hereby confirmed.

Claims

A method for producing an activated silane characterized in that
a silane, selected from the group comprising: mono-, di-, and trialkoxysilanes including a C₁ to C₈ alkoxy group, wherein the alkoxysilane carries at least one C₂ to C₁₀ aminoalkyl group or a C₂ to C₁₀ N-aminoalkyl group; 3(2-aminoethylamino)propyl-trimethoxysilane; (MeO)₃-Si-(CH₂)₃-NH-(CH₂)₃-Si-(OMe)₃; 3-aminopropylsilanetriol; aminosilane with ethoxylated nonyl-phenolate; phenyl-CH₂-NH-(CH₂)₃-NH-(CH₂)₃-Si-(OMe)₃*HCl; as well as mixtures thereof

is reacted with

an open-chain or cyclic acetal or semiacetal or geminal diol of a ketone according to Formula (1):

including at least one carbonyl group which forms an acetal or semiacetal with a C₁ to C₁₂ alkyl or cycloalkyl alcohol, or which forms a geminal diol with water;

wherein R1 and R2, being identical or different, are independently selected from the group comprising: H; C₁ to C₉ alkyl; C₂ to C₉ alkenyl including 1 - 4 double bonds, C₁ to C₉ hydroxyalkyl; aryl including 5 or 6 C atoms in the cycle or heteroaryl including 1 - 4 hetero atoms and 4-8 C atoms in the cycle, cycloalkyl including 5 - 10 C atoms, heterocycloalkyl including 1 - 4 hetero atoms and 4 - 8 C atoms in the cycle, carbonyl, carboxyl, C₁ to C₉ n-alkylcarbonyl having a position of the carbonyl function of 1- 9, C₁ to C₉ alkoxycarbonyl, wherein the alkyl residue in particular is methyl, ethyl, propyl, or butyl;

and wherein the acetal, semiacetal or geminal diol corresponds to the following general Formula (2):

wherein R3 and R4, being identical or different, independently is C₁ to C₁₂ alkyl or C₁ to C₁₂ cycloalkyl or H, and R1 and R2 have the same meaning as in Formula (1)

or

wherein R3 is an n-alkyl residue including 2 - 5 C atoms, and R1 and R2 have the same meaning as in Formula (1) or R1 and R2 is equal to H and R3 is equal to 2-oxypropyl,
or

the silane is reacted with mixtures of the named acetals and geminal diols.
The method according to claim 1, characterized in that the silane is 3-aminopropyltriethoxysilane.
The method according to claim 1 or 2, characterized in that several carbonyl groups in the ketone according to Formula (1) are acetalized.
The method according to claims 1 to 3, characterized in that the ketone is selected from the group comprising: dihydroxyacetone; monohydroxyacetone; acetylacetone.
The method according to claims 1 to 4, characterized by charging, preferably in a tank equipped with a mechanical stirrer, water, preferably dilution water, for starting a binder composition;
adding the corresponding quantity of the carbonyl compound and corresponding alcohol or the acetal and/or geminal diol, and stirring until complete dissolution, wherein for compounds poorly soluble in water, careful heating is optionally performed, or a dispersing aid is added while stirring vigorously;

the silane is added to this solution; and

stirring is continued until a distinct change of color of the solution.